Turbo Replacement on Mercedes S-Class W221 3.0 Diesel OM642. • Turbocharger fault, loss of power, and limp mode are common issues on diesel Mercedes vehicles equipped with the OM642 engine. In this video, I show the turbocharger replacement process on a Mercedes-Benz S-Class W221 with the 3.0 OM642 diesel engine. • The job is relatively quick and straightforward because the turbocharger on this engine is mounted on top, in the V of the cylinder block, which provides good access without major dis